Sword and rapier sedges (Lepidosperma, Cyperaceae) are common in the southern Australian and New Zealand floras, also occurring in New Caledonia and South-east Asia. Sedge ecology is seldom studied and Barrett provides the first comprehensive review. He considers that Lepidosperma species are important components of many ecosystems; unusually, the majority of species occur in mesic habitats. Speciation patterns in the genus are of considerable interest due to complex biogeographic patterns and habitat specificity. Potential benefits exist for medicinal products identified from several Lepidosperma species. Over 165 organisms are found to be dependent on, or making use of Lepidosperma species, showing that sedges clearly play a critical role in many ecosystems – an importance that is often overlooked.